In temperate, sub-tropical and tropical climates, swimming pools are common additions to dwellings. Unfortunately swimming pools require a considerable amount of maintenance much of which is concerned with the removal of debris, usually leaf or other vegetation litter, which falls into the pool.
Litter falling into a swimming pool can conveniently be divided into matter which sinks to the bottom of the pool and matter which floats on the surface of the pool. A wide range of pool cleaning devices have been developed to clean matter on the submerged surfaces of the pools and matter floating on the surface of a pool.
Matter floating on the surface of swimming pools is usually cleaned by draining the water over a trap arrangement which is located in or near the inlet of the swimming pool weir. In this manner water pumped through the pool's filters is drawn through the cleaner and skimmer.
Because these skimmers are located at the inlet of the weir they have a disadvantage in that they can clog or be rendered ineffective by leaf litter and other floating matter. In both instances the inlet, or in some cases a by-pass inlet to the pump can become constricted which can result in the pump overheating or adverse operating conditions for the pool cleaner can occur or both.
Various other proposals have been made to provide for surface skimming of a pool in order either to overcome disadvantages with the built-in type described above or to supplement them.
Thus, for example, Henk in U.S. Pat. No. 4,501,659 describes a surface skimmer which is fixed to the wall of a pool at the inlet for return water from a swimming pool filter and in this case the skimmer has a housing of sector-shape in cross-section with the flat face secured to the wall. The inlet for return water is jetted straight out of the outlet into an outlet arranged co-axially therewith in the bottom of the housing. A buoyant sleeve is arranged to have its periphery just below the water level so that the upper film of water flows into the housing via the sleeve. The upper end of the sleeve supports a net or basket for catching leaves and other debris flowing into the housing.
The disadvantages of this arrangement are firstly that the basket or net, being internally located, is severely limited as to its capacity unless the housing and sleeve are made to large proportions. Secondly, the jet of water emitted from the housing is directed straight out to the middle of the pool and this is considered to be undesirable, as it may disturb swimmers unnecessarily. Thirdly, the general flow of debris is from the centre of the pool towards the skimmer and there is substantially no flow along the side of the pool. Finally, because of the fact that the flat side of the housing is secured very close to the swimming pool wall, this provides a site for the growth of algae and accumulation of dirt which cannot be easily cleaned, save by removal of the housing completely.
Various other proposals have been put forward wherein the skimmer itself is attached by way of a long flexible suction pipe to either a swimming pool filter pump inlet or outlet to promote a flow of water through the skimmer and such skimmers move around the swimming pool generally completely arbitrarily. Such skimmers are not considered by applicant to be useful as they obstruct and impede swimmers and, in fact, can cause injury in the event that swimmers are not careful.